Magnetization

Magnetization

Why did we not get the results (e.g. lower flux, higher noise, different flux pattern etc) as what we have expected?

  • The bonded Neo magnets may not be fully saturated (Refer to page 19 in the Magnetization Guide).
    The most common reason for not achieving what is expected from bonded Neo is not achieving full saturation of the bonded Neo magnets during magnetization. Bonded Neo requires more applied magnetic field for saturation than what is required for ferrite. It is often the case that magnetizing equipment that is designed for magnetization of ferrite or sintered Neo will not magnetize bonded Neo properly. A magnetizing fixture requires approximately 3 Tesla to saturate bonded Neo. Performing an experiment to generate a saturation curve is a good way to determine if magnets are fully saturated. Check with Magnequench or a magnetic equipment vendor for help with magnetization of prototype or production quantities.
  • The bonded Neo magnets may not be oriented properly (Refer to pages 14, 15, 20, & 23 in the Magnetization Guide).
    Bonded Neo is isotropic and is oriented during magnetization. Radial orientation usually provides the highest flux levels, and lower than expected flux can be a result of orientation that is not radial. FEA design tools or experience with magnetization of bonded Neo is usually required to achieve the magnet orientation that is appropriate for good operation of a motor. Any orientation may be achieved – radial, trapezoidal, sinusoidal, or anything in between. Check with Magnequench or a magnetic equipment vendor for help with magnetization of prototype or production quantities.
  • The application's magnetic circuit may not be properly designed for bonded Neo.
    Each magnetic material is unique with regard to strength, orientation, physical characteristics, etc. A motor or other magnetic circuit that has been designed for one type of magnetic material will probably not work with a different type of magnetic material. Often, motors utilizing ferrite magnets require 2 to 3 times the magnet mass that is required for bonded neo. If bonded Neo is simply used to replace ferrite magnets without redesigning the rest of the magnetic circuit, many problems might arise, such as oversaturation of soft magnetic components. The Magnequench applications team is available for consultation on the best magnetic circuit design practices for bonded Neo.
  • The higher air gap flux of the bonded neo may be causing more noise and vibration.
    Many of the advantages of bonded Neo, such as higher efficiency and smaller motor size, are derived by using higher air-gap flux density than is present in a ferrite motor. Unless the magnetic circuit and the magnet orientation are optimized for this higher air-gap flux density, greater cogging torque may occur. Bonded Neo can easily be magnetized to a variety of orientations that result in both higher efficiency and lower cogging torque. You can also consider magnetizing a skew angle on your magnet – something that is very easy to do with bonded Neo. If you are experiencing increased noise or cogging with bonded Neo feel free to consult the Magnequench applications team on the best magnetic circuit design practices for bonded Neo.
    http://www.mqitechnology.com/downloads/articles/MagnetizingGuide.pdf

Why are we are having trouble in getting radial orientation?

Bonded Neo is isotropic and is oriented during magnetization. (Refer to page 23 in the Magnetization Guide) Any orientation may be achieved – radial, trapezoidal, sinusoidal, or anything in between, but FEA design tools or experience with magnetization of bonded Neo is usually required to achieve the magnet orientation that is proper for good operation of a motor. Check with Magnequench or a magnetic equipment vendor for help with magnetization of prototype or production quantities.
http://www.mqitechnology.com/downloads/articles/MagnetizingGuide.pdf

What are the possible magnetization profiles when using a bonded Nd magnet?

With bonded Neo any orientation may be achieved – radial, trapezoidal, sinusoidal, or anything in between. And since bonded Neo is isotropic and the orientation is determined during magnetization it is possible to try many different magnet orientations in one motor design simply by changing the magnetizing fixture. Not only is any orientation possible but also magnetizing the magnet with any desired skew angle is possible. FEA design tools or experience with magnetization of bonded Neo is helpful for achieving the best magnet orientation for good operation of a motor. Check with Magnequench or a magnetic equipment vendor for help with magnetization of prototype or production quantities.

How are the magnetization profiles of bonded Neo magnets different from those of other magnets?

Most other materials such as Sintered Ferrite and Sintered Neo are anisotropic. This meant that they are oriented during magnet manufacturing and not during magnetization. Achieving the desired flux profiles, such as radial, trapezoidal, or sinusoidal usually requires designing these anisotropic magnets to a special shape, and the design of the magnetizing fixture is less critical for anisotropic material than it is for isotropic material. As with isotropic bonded Neo nearly any magnetization profile can be achieved as compared to anisotropic materials. The difference is that bonded Neo profiles are more dependent on the magnetizing fixture and less dependent on the magnet design, while for anisotropic materials profiles are more dependent on the magnet design.

We have a magnetizer and a magnetizing fixture already. Can we use our existing equipment to magnetize bonded Neo magnets?

It may be possible to use your existing equipment to magnetize bonded Neo, however bonded Neo generally requires higher energy for magnetization that either sintered Neo or Sintered Ferrite. It is often the case that magnetizing equipment that is designed for magnetization of ferrite or sintered Neo will not properly magnetize bonded Neo. A magnetizing fixture requires approximately 3 Tesla to saturate bonded Neo. Performing an experiment to generate a saturation curve is a good way to determine if magnets are fully saturated. Check with Magnequench or a magnetic equipment vendor for help with magnetization of prototype or production quantities.

What can I do if I need help magnetizing bonded Neo?

The Magnequench applications team has many years of experience designing and building magnetizing fixtures for bonded Neo, and we are happy to provide assistance. Our experience dates back to the earliest commercial uses of bonded Neo and takes advantage of the newest technologies such as FEA calculation of magnetization and low-impedance magnetizers. Also, there are many commercial providers of magnetization equipment who are experienced with magnetization of bonded Neo.